Question BCP

So back in august I got severe tonsillitis and was on antibiotics for over a month and on and off steroids plus I had surgery to get them out. During this time I started getting my periods in the middle of the pack but still normal flow and symptoms and on time. Now I’m about a month out from surgery and I just started the last week in my pack and I haven’t gotten my period yet. I was thinking it was because my body is going back to normal and I’m not on a bunch of medications that mess with bcp anymore. But I’m just a little nervous. Thoughts?